Quantifying the statistics of CMB-lensing-derived galaxy cluster mass measurements with simulations

TL;DR

This paper investigates the statistical properties of galaxy cluster mass measurements derived from CMB lensing, using simulations to assess bias, scatter, and deviations from log-normality for Planck-like experiments.

Contribution

It provides a detailed analysis of the bias and scatter in CMB lensing-based cluster mass estimates, including the effects of large-scale structure and deviations from log-normality.

Findings

Bias and scatter quantified for Planck-like experiments

Deviations from log-normality have negligible impact on mass calibration

Results discussed for higher resolution, lower noise experiments

Abstract

CMB lensing is a promising, novel way to measure galaxy cluster masses that can be used, e.g., for mass calibration in galaxy cluster counts analyses. Understanding the statistics of the galaxy cluster mass observable obtained with such measurements is essential if their use in subsequent analyses is not to lead to biased results. We study the statistics of a CMB lensing galaxy cluster mass observable for a Planck-like experiment with mock observations obtained from an N-body simulation. We quantify the bias and intrinsic scatter associated with this observable following two different approaches, one in which the signal due to the cluster and nearby correlated large-scale structure is isolated, and another one in which the variation due to uncorrelated large-scale structure is also taken into account. For our first approach we also quantify deviations from log-normality in the scatter, finding them to have a negligible impact on mass calibration for our Planck-like experiment. We briefly discuss how some of our results change for experiments with higher angular resolution and lower noise levels, such as the current generation of surveys obtained with ground-based, large-aperture telescopes.